Where does the asteroid come from ? In the Baut Forum someone remembered another celestial body was later identified as being a part of afaik a Saturn rocket , and had the thought also 2009BD might be a human made object , given it small size ( several meters) . It's possible ...if the current orbit varies from the nonimal orbit . Given the JPL nominal orbital parameters the object must have been close to Earth around june 1955, at a distance of about 0.003 AU . This close approach was two years before the first Russian Sputnik , which was I think the first launched sattelite , so this object is probably not man made . In annex a simulation in rotating frame to Earth , going back in time .

Nice animation. I had not thought about the Centaur Chariklo. I know that Chariklo is suppose to be near the 4:3 Uranus resonance. (Horner 2004) I suppose this animation is showing Chariklo "displaying resonant like behaviour".

Unfortunately Chariklo doesn't seem to have a 4:3 resonance to Uranus if we keep Uranus fixed . The pattern is very unusual but the orbit doesn't match a resonance Animation was run for 20.000 years .

I am glad that Chariklo does not show a resonance. Other wise it would likely be in conflict with the findings of Horner 2004. The current JPL orbital data is based on 532 observations spanning 20 years (through 2008-07-03) with an orbit quality of 1. So it is near the resonance but misses it.

how come my chairiklo seems to liberate? And how do you get your planets in a straight line, mine make an oval?

In order to get the resonance presented you should adapt the rotating frame setting to the correct orbital period . This makes the primary stable . This wasn't the case in your animation . Once this is done Uranus will make an oval which will stay at its location . One can also take the asteroid as the primary , but this isn't generally done . The reason why Uanus makes a straight line in my visualisation is that I used my own simulator (similar to GravSim ) . Here I adapt the screenshot continiously in order to position the orbit of the primary at a fixed angle . So while the angle is fixed Uranus orbit shows up as a line due to its eccentricity . If eccentricity would be zero the primary will show up as a point .

Amycus seems to be sandwitched between the orbits of Uranus and Neptune . The animation covers ca. 25.000 years . Uranus appears in rotating frame to it as the blue line at 3 'o clock . ( each frame covers 3*84.07 yeras) . Neptune in white . Amycus can hold its wildly librating 3:2 resonance to Uranus for about 12.000 years , but then , probably due to a to close encounter with Uranus it breakes up the resonance.

how come my chairiklo seems to liberate? And how do you get your planets in a straight line, mine make an oval?

In order to get the resonance presented you should adapt the rotating frame setting to the correct orbital period . This makes the primary stable . This wasn't the case in your animation . Once this is done Uranus will make an oval which will stay at its location . One can also take the asteroid as the primary , but this isn't generally done . The reason why Uanus makes a straight line in my visualisation is that I used my own simulator (similar to GravSim ) . Here I adapt the screenshot continiously in order to position the orbit of the primary at a fixed angle . So while the angle is fixed Uranus orbit shows up as a line due to its eccentricity . If eccentricity would be zero the primary will show up as a point .

I used the preset thing... but why does it liberate? I don't understand

[quote author=NeutronStar link=1175113160/195#208 date=1234632616 Can I download it, or do you think it would be confusing? [/quote] I'm afraid the simulator isn't very useful for the public . It misses a lot of nice input and output features GravSim has . Input has to be done manually and there's no correction possible once the sim is started . I use both programs . GravSim is much better for input and visualisation and performs very well even for large systems. One advantage : the integrator adapts its timestep in order to get a preset accurancy . We once tried to combine the integrator with GravSim but this wasn't a succes till now.